The present invention relates to a specimen prepared for quantitative evaluation of the resolving power/resolution performance of an electron microscope, a method of evaluating and adjusting the electron microscope resolving power using the prepared specimen, an electron microscope capable of quantitative evaluation of the resolving power thereof, and a method of fabricating semiconductor devices using the electron microscope.
Conventionally, the resolving power of an electron microscope is evaluated using the distance between two points visible on a specimen. In Japanese Non-examined Patent Publication No. 45265/1993, there is disclosed an electron microscope resolving power evaluation method in which a gold-particle-evaporated carbon specimen is observed with an electron microscope and the resolving power thereof is determined based on a minimum distance between two gold particles. Also, electron microscope resolution is evaluated based on a degree of blurring on a particle boundary.
In the conventional resolving power evaluation method using gold-particle images observed with an electron microscope, variations in size and shape of the gold particles cause differences in the results of measurement among individual analysts and identical specimens are not reproducible, making it difficult in practice to obtain accurate quantitative evaluation of the resolving power. Furthermore, no method is available for accurately measuring a distance between gold particles under electron microscope observation, and there is an instrumental error in resolving power among individual electron microscopes. Therefore, in semiconductor device fabrication, where the dimensions of circuit patterns on a semiconductor device are measured using a plurality of electron microscopes, an observed image of each semiconductor device may differ among electron microscopes, resulting in a problem that a defect is observable or not observable depending on the electron microscope being employed. As a consequence, it is not possible to implement semiconductor device fabrication based on predetermined consistent control data values.